Multiple Sclerosis Diagnostic Criteria

One of the reasons that multiple sclerosis (MS) can be so difficult to diagnose is that neurologists (physicians who specialize in the diagnosis and treatment of nervous system disorders) haven’t yet found any specific tests that can be used to identify it. For example, you can’t culture it like you do with strep throat, or detect it with a blood test like you can with diabetes.

Instead, an MS diagnosis is a clinical one, which means that the doctor pieces it together from a variety of sources, including your personal and family history, the symptoms you report, the findings on the neurologic examination, and whatever other tests may be needed. So, if you go in with problems or symptoms that may indicate MS, your primary care physician may recommend that you see a neurologist to help sort out the evidence.

In order to make a diagnosis of MS, your doctor must find objective evidence of dissemination in time and space. Yes, it’s truly a mouthful, but it’s a good term to know because it’s the basis for the long-established diagnostic criteria for multiple sclerosis. In a nutshell, what this term means is:

The diagnosis requires objective evidence of two relapses (in other words, two episodes of demyelination in the central nervous system (CNS), which includes the brain, spinal cord, and optic nerves). Demyelination is the term used to describe the damage caused to the myelin coating surrounding the nerve fibers.

A relapse (also known as an attack, exacerbation, episode, or flare) is defined as the sudden appearance or worsening of an MS symptom (or symptoms) that lasts at least 24 hours (although in reality, most attacks last several days or weeks).

The two relapses must be separated in time (by at least one month) and in space (as evidenced by areas of inflammation or damage in different areas of the CNS).

There must be no other explanation for these relapses or for the symptoms that the person is experiencing. In other words, the physician must rule out all other possible diseases or conditions that may be causing the neurological problems.

The diagnosis of MS requires evidence of at least two relapses that have occurred in different parts of the central nervous system and different points in time, but now more tools are at the neurologist’s disposal for collecting that evidence.

The criteria for diagnosing MS continue to be a work in progress, and new revisions help enhance the speed and accuracy of an MS diagnosis. You can take a peek at the specifics from the National Multiple Sclerosis Society.